margolin<-structure(list(y = c(15, 21, 29, 16, 18, 21, 16, 26, 33, 27, 
41, 60, 33, 38, 41, 20, 27, 42), x = c(0, 0, 0, 10, 10, 10, 33, 
33, 33, 100, 100, 100, 333, 333, 333, 1000, 1000, 1000)), .Names = c("y", 
"x"), row.names = c(NA, 18), class = "data.frame")
